Rotor punching sheet and motor rotor iron core
By setting multiple positioning holes and interference-fitting rotary shaft design on the rotor punch, the problem of vibration noise and production costs of permanent magnet synchronous motors at high speeds is solved, and low-cost and efficient assembly and noise control are achieved.
Patent Information
- Application Number
- CN202421763556.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-24
- Publication Date
- 2025-07-01
- Estimated Expiration
- 2034-07-24
AI Technical Summary
The existing permanent magnet synchronous motors have problems with increasing vibration noise and production costs at high speeds, especially because the gap between the rotor core and the shaft becomes larger and the concentricity is poor, which makes it difficult for the vibration noise to meet the requirements. At the same time, multiple sets of molds increase production costs.
A rotor punching piece is designed, by setting multiple positioning holes on the annular body, adjusting the posture of the annular body using the positioning tool to realize the deflection angle of the segmented oblique pole. The rotor punching piece is intersected with the rotating shaft to avoid grooves on the rotating shaft, and only one set of molds is required to produce.
It effectively reduces the production cost of the motor, improves assembly efficiency, reduces vibration noise, and meets the motor's control requirements for noise and cost.
Smart Images
Figure CN223052818U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of motors, and particularly relates to a rotor punching sheet and a motor rotor core. Background Art
[0002] Most driving motors of new energy vehicles adopt permanent magnet synchronous motors, which have excellent performances such as small volume and high power density. For such motors, air-gap harmonics, cogging torque, torque ripple, and vibration noise are problems to be solved urgently. In the prior art, the rotor segmented skew pole technology is generally adopted to solve the above problems. Specifically, the rotor core includes a plurality of core segments, keys are distributed on the inner circle of the core segments, and according to the requirements of the skew pole angle, the positions of the keys of the core segments relative to the center line of the permanent magnet are different. Through the cooperation of the keys of the plurality of core segments and the key grooves on the rotating shaft, a skew pole rotor structure with a required angle is formed.
[0003] In this technology, the rotor core and the rotating shaft are mostly in clearance fit. As the motor speed increases, the deformation amount of the rotor core increases, the clearance with the rotating shaft becomes larger, and the concentricity between the core and the rotating shaft becomes worse, making it difficult to meet the vibration and noise requirements of the whole vehicle. Since the positions of the keys of different core segments are different, correspondingly different-shaped rotor punching sheets are required, and thus multiple sets of dies are needed during stamping, resulting in an increase in the production cost of the motor. And the rotating shaft cooperating with the rotor core needs to be provided with key grooves, which also increases the processing difficulty and cost of the rotating shaft.
[0004] Therefore, in view of the above technical problems, it is necessary to provide a rotor punching sheet and a motor rotor core. Summary of the Utility Model
[0005] The purpose of the utility model is to provide a rotor punching sheet and a motor rotor core, which can solve the problems of vibration and noise during high-speed operation of the motor and the increase in production cost and production difficulty of the motor.
[0006] In order to achieve the above purpose, the technical solution provided by a specific embodiment of the utility model is as follows:
[0007] A rotor punching sheet includes an annular body having a shaft hole, and the annular body is provided with a positioning hole, and the positioning hole includes a first hole position and a second hole position that can be respectively matched with a positioning tooling;
[0008] Wherein, when the annular body is in the first posture, the positioning hole is matched with the positioning tooling in a predetermined posture through the first hole position; when the annular body is in the second posture, the positioning hole is matched with the positioning tooling in a predetermined posture through the second hole position; a first predetermined deflection angle is provided between the first posture and the second posture of the annular body along its ring center axis.
[0009] In one or more embodiments of the present utility model, the positioning hole further includes a third hole position that cooperates with the positioning tooling. When the annular body is in the third posture, the positioning hole cooperates with the positioning tooling in a predetermined posture through the third hole position; a second predetermined deflection angle is provided along the central axis of the annular body between the second posture and the third posture of the annular body;
[0010] Wherein, when the annular body deflects from the first posture to the third posture, the annular body deflects the sum of the first predetermined deflection angle and the second predetermined deflection angle along its central axis.
[0011] In one or more embodiments of the present utility model, the centers of the first hole position, the second hole position, and the third hole position are distributed in an annular array on a reference circumference, where the reference circumference is a circumference centered on the center of the annular body; and / or,
[0012] The first hole position, the second hole position, and the third hole position are interconnected, and there is an overlapping portion between the first hole position and the second hole position, and there is an overlapping portion between the second hole position and the third hole position.
[0013] In one or more embodiments of the present utility model, the inner peripheral wall of the positioning hole includes a first inner peripheral wall section defining the first hole position, a second inner peripheral wall section defining the second hole position, and a third inner peripheral wall section defining the third hole position. The vertical projections of the first inner peripheral wall section, the second inner peripheral wall section, and the third inner peripheral wall section on the plane where the annular body is located are arcs.
[0014] In one or more embodiments of the present utility model, the first inner peripheral wall section and the third inner peripheral wall section of the annular body are recessed with positioning key grooves that can cooperate with the positioning tooling, and the second inner peripheral wall of the annular body is protruded with positioning keys that can cooperate with the positioning tooling.
[0015] In one or more embodiments of the present utility model, the centers of the first hole position and the second hole position are distributed in an annular array on a reference circumference, where the reference circumference is a circumference centered on the center of the annular body; and / or,
[0016] The annular body is provided with a limiting structure for cooperating with the positioning tooling in the first hole position and the second hole position.
[0017] In one or more embodiments of the present utility model, the annular body is provided with a plurality of the positioning holes, and the centers of the first hole position and the second hole position in the plurality of positioning holes are distributed in an annular array on a reference circumference; and / or
[0018] The inner peripheral wall of the shaft hole of the annular body does not include a limiting structure, and the vertical projection of the shaft hole of the annular body on the plane where it is located is circular.
[0019] A rotor punching technical solution provided by a specific embodiment of the utility model is as follows:
[0020] A rotor punching comprises an annular body with an axial hole, the annular body is provided with a positioning hole, the vertical projection of the positioning hole on the plane where the annular body is located comprises a first arc, a second arc and a third arc which are connected to each other in sequence, the first arc, the second arc and the third arc have the same radius of curvature, and the centers of the circles where the first arc, the second arc and the third arc are located are located on the same circumference with the center of the annular body as the center.
[0021] In one or more embodiments of the present invention, the angle between the center of the circle where the first arc and the second arc are located and the line connecting the center of the annular body is equal to the angle between the center of the circle where the second arc and the third arc are located and the line connecting the center of the annular body, and the angle is set to achieve a predetermined deflection angle for realizing the skew pole mode of the motor rotor.
[0022] A specific embodiment of the utility model also provides a motor rotor core, and the technical solution is as follows:
[0023] A motor rotor core comprises the above-mentioned rotor punching sheet and a rotating shaft which is interference-fitted with the shaft hole of the annular body of the rotor punching sheet.
[0024] Compared with the prior art, the rotor punching of the utility model is provided with positioning holes with different hole positions. When the positioning tool cooperates with different hole positions in a predetermined posture, the annular body of the rotor punching will deflect along its annular axis. In this way, through reasonable arrangement of hole positions, the rotor punchings that cooperate with the positioning tooling can have a predetermined deflection angle, so as to realize the setting of segmented oblique poles; at the same time, since the positioning hole does not need to be set at the shaft hole of the rotor punching, and there is no need to slot the shaft hole, the motor shaft can cooperate with the rotor punching in an interference fit manner, so as to meet the motor's requirements for noise control, cost control, and speed. In addition, since only one rotor punching needs to be processed and produced, that is, only one set of stamping dies is needed, the production cost of the motor can be effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0026] Figure 1 This is a schematic diagram of the structure of the rotor punching in one embodiment of the utility model;
[0027] Figure 2 Schematic diagram of the structure during the assembly of the rotor punching sheet and the positioning tooling in an embodiment of the present utility model;
[0028] Figure 3 Enlarged schematic diagram of the positioning hole in an embodiment of the present utility model;
[0029] Figure 4 Schematic simplified diagram of the positioning hole in an embodiment of the present utility model;
[0030] Figure 5 Enlarged schematic diagram of the positioning hole and the magnet slot group in an embodiment of the present utility model;
[0031] Figure 6 Assembly schematic diagram of the positioning tooling and the first hole position in an embodiment of the present utility model;
[0032] Figure 7 Assembly schematic diagram of the positioning tooling and the second hole position in an embodiment of the present utility model;
[0033] Figure 8 Assembly schematic diagram of the positioning tooling and the third hole position in an embodiment of the present utility model.
[0034] Description of the main reference numerals:
[0035] 1. Ring-shaped body; 2. Shaft hole; 3. Positioning hole; 31. First hole position; 311. First arc; 32. Second hole position; 321. Second arc; 33. Third hole position; 331. Third arc; 4. Positioning key groove; 5. Positioning key; 6. Magnet slot; 7. Magnet. Detailed implementation manners
[0036] In order to enable those skilled in the art to better understand the technical solutions in the present utility model, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.
[0037] Refer to Figure 1 and Figure 2 , in an embodiment of the present utility model, a rotor punching sheet is provided, which includes a ring-shaped body 1 having a shaft hole 2. The ring-shaped body 1 is provided with a positioning hole 3, and the positioning hole 3 includes a first hole position 31, a second hole position 32, and a third hole position 33 (see Figure 2 mark a) that can be respectively matched with the positioning tooling (see Figure 4 ).
[0038] Among them, when the annular body 1 is in the first posture, the positioning hole 3 cooperates with the positioning tooling in a predetermined posture through the first hole position 31; when the annular body 1 is in the second posture, the positioning hole 3 cooperates with the positioning tooling in a predetermined posture through the second hole position 32; when the annular body 1 is in the third posture, the positioning hole 3 cooperates with the positioning tooling in a predetermined posture through the third hole position 33. The predetermined posture of the positioning tooling refers to the position state of the positioning tooling passing through the positioning hole 3. After the positioning tooling is adjusted to the predetermined posture and remains stationary, at this time, by adjusting the annular body 1 to different postures, it can cooperate with the predetermined posture of the positioning tooling. Different postures of the annular body 1 are states where the annular body 1 is at different rotation angles along its ring center axis.
[0039] Specifically, a first predetermined deflection angle is provided along the ring center axis between the first posture and the second posture of the annular body 1. A second predetermined deflection angle is provided along the ring center axis between the second posture and the third posture of the annular body 1. When the annular body 1 deflects from the first posture to the third posture, the annular body 1 deflects by the sum of the first predetermined deflection angle and the second predetermined deflection angle along its ring center axis. The first predetermined deflection angle and the second predetermined deflection angle refer to the relative rotation angles existing between the annular bodies 1 when installing a plurality of annular bodies 1, so as to be assembled to form a Figure 2 segmented skewed pole electrode rotor core as shown.
[0040] Specifically, referring to Figure 3 and Figure 4 , the centers of the first hole position 31, the second hole position 32, and the third hole position 33 are annularly arrayed on the reference circumference. Among them, the reference circumference is a circumference with the center of the annular body 1 as the center. The first hole position 31, the second hole position 32, and the third hole position 33 are interconnected with each other, and there is an overlapping part between the first hole position 31 and the second hole position 32, and there is an overlapping part between the second hole position 32 and the third hole position 33.
[0041] In this embodiment, the inner peripheral wall of the positioning hole 3 includes a first inner peripheral wall segment defining the first hole position 31, a second inner peripheral wall segment defining the second hole position 32, and a third inner peripheral wall segment defining the third hole position 33. The perpendicular projections of the first inner peripheral wall segment, the second inner peripheral wall segment, and the third inner peripheral wall segment on the plane where the annular body 1 is located are arcs.
[0042] Referring to Figure 3 and Figure 4, The perpendicular projections of the first inner peripheral wall segment, the second inner peripheral wall segment, and the third inner peripheral wall segment on the plane where the annular body 1 is located include a first arc 311, a second arc 321, and a third arc 331 that are sequentially connected to each other. The first arc 311, the second arc 321, and the third arc 331 have the same radius of curvature, and the centers of the circles where the first arc 311, the second arc 321, and the third arc 331 are located are on the same circumference with the center of the annular body 1 as the center of the circle. Among them, as Figure 4 shown, the second arc 321 includes two arcs located on the same circumference.
[0043] The included angle between the connecting line between the center of the circle where the first arc 311 and the second arc 321 are located and the center of the annular body 1 is equal to the included angle between the connecting line between the center of the circle where the second arc 321 and the third arc 331 are located and the center of the annular body 1. The included angle is set to a predetermined deflection angle for realizing the skewed pole mode of the motor rotor.
[0044] Specifically, in this embodiment, the included angle between the connecting line between the center of the circle where the first arc 311 and the second arc 321 are located and the center of the annular body 1 is the first predetermined deflection angle. The included angle between the connecting line between the center of the circle where the second arc 321 and the third arc 331 are located and the center of the annular body 1 is the second predetermined deflection angle. The first predetermined deflection angle is equal to the second predetermined deflection angle. In this embodiment, both the first predetermined deflection angle and the second predetermined deflection angle are set to 2.5° (the specific calculation method is shown below). In other embodiments, the first predetermined deflection angle and the second predetermined deflection angle can also be set to be unequal.
[0045] Among them, the same radius of curvature of the first arc 311, the second arc 321, and the third arc 331 is convenient for matching the shape and size of the positioning tooling. The centers of the circles where the first arc 311, the second arc 321, and the third arc 331 are located are on the same circumference with the center of the annular body 1 as the center of the circle, which is convenient for adjusting its position to the first posture, or the second posture, or the third posture by rotating along the central axis of the annular body 1.
[0046] Referring to Figure 3 , positioning key grooves 4 that can cooperate with the positioning tooling are recessed in the first inner peripheral wall segment and the third inner peripheral wall segment of the annular body 1, and a positioning key 5 that can cooperate with the positioning tooling is protruded on the second inner peripheral wall of the annular body 1. Combining Figure 2 , the positioning tooling in this application is set as a circular rod, and keys and key grooves are cooperatively arranged on the circular rod.
[0047] Referring to Figure 1 and Figure 5, the annular body 1 is provided with a plurality of positioning holes 3, and the centers of the first hole position 31 and the second hole position 32 among the plurality of positioning holes 3 are annularly arrayed on a reference circumference. In this embodiment, two positioning holes 3 are set as a group, and the centers of multiple groups of positioning holes 3 are also annularly arrayed on the reference circumference. A group of positioning holes 3 is symmetrically arranged about its center line, and the center line is a straight line passing through the center of the annular body 1 and having an equal perpendicular distance from the centers of the adjacent positioning holes 3.
[0048] Referring to Figure 1 and Figure 2 , the inner peripheral wall of the shaft hole 2 of the annular body 1 does not include a limiting structure, and the vertical projection of the shaft hole 2 of the annular body 1 in its plane is circular. Therefore, it is convenient to perform an interference fit connection with the rotating shaft through the shaft hole 2.
[0049] Referring to Figure 2 , when assembling multiple rotor punching sheets, first adjust the positioning tooling ( Figure 2 shown by the mark a) to a predetermined posture, and then sequentially assemble multiple rotor punching sheets onto the positioning tooling. Specifically:
[0050] Referring to Figure 2 and Figure 6 , when assembling the first rotor punching sheet, adjust the annular body 1 to the first posture so that the first hole position 31 of the annular body 1 is fitted and installed with the positioning tooling. At this time, the first inner peripheral wall section of the annular body 1 abuts against the positioning tooling, and the rotation of the annular body 1 is restricted by the key and keyway located at this position.
[0051] Referring to Figure 2 and Figure 7 , when assembling the second rotor punching sheet, adjust the annular body 1 to the second posture so that the second hole position 32 of the annular body 1 is fitted and installed with the positioning tooling. At this time, the second inner peripheral wall section of the rotor punching sheet abuts against the positioning tooling, and the rotation of the rotor punching sheet is also restricted by the key and keyway located at this position. Among them, since the included angle between the connecting lines of the centers of the circles where the first arc 311 and the second arc 321 are located and the center of the annular body 1 is a first predetermined deflection angle. Therefore, a relative rotation of the first predetermined deflection angle is achieved between the first rotor punching sheet and the second rotor punching sheet.
[0052] Referring to Figure 2 and Figure 8, when assembling the third rotor punching sheet, adjust the annular body 1 to the third posture so that the third hole position 33 of the annular body 1 is fitted and installed with the positioning tooling. At this time, the third inner peripheral wall section of the annular body 1 abuts against the positioning tooling, and the rotation of the rotor punching sheet is also restricted by the key and keyway located there. Among them, since the included angle between the connecting lines of the centers of the circles where the second arc 321 and the third arc 331 are located and the center of the annular body 1 is the second predetermined deflection angle. Therefore, a relative rotation of the second predetermined deflection angle is achieved between the second rotor punching sheet and the third rotor punching sheet.
[0053] Therefore, through the above assembly method, the positioning and installation of multiple rotor punching sheets can be completed, so as to facilitate the subsequent production of the motor rotor core. In the traditional technical solution, it is necessary to provide a keyway on the inner peripheral wall of the rotating shaft to cooperate with a predetermined deflection angle. Therefore, in the assembly of the traditional rotor punching sheet, it is necessary to distinguish its A and B surfaces, and different molds are also required to produce corresponding rotor punching sheets. In this application, since there is no limiting structure on the inner peripheral wall of the rotating shaft and the positioning holes 3 are distributed in a circumferential ring shape. Therefore, when assembling the rotor punching sheet, it is not necessary to distinguish the A and B surfaces, and only one set of molds is required to produce one specification of rotor punching sheet to realize the adjustment of different deflection angles of the rotor punching sheet. Therefore, the utility model can effectively reduce the production cost of the motor and improve the assembly efficiency of the rotor punching sheet at the same time.
[0054] It can be understood that the positioning holes 3 are not only used for fitting and installing with the positioning tooling, but also for weight reduction. By reducing the weight of the rotor punching sheet, the driving burden of the motor can be effectively reduced, and the high-speed operation of the motor can be ensured.
[0055] Refer to Figure 1 and Figure 5 , in this embodiment, the rotor punching sheet is also provided with multiple sets of magnet slots 6, and magnets 7 are inserted into the magnet slots 6. The centers of the multiple sets of magnet slots 6 are arranged in a circular array on another reference circumference, and the number of sets of the magnet slots 6 is the same as the number of the positioning holes 3, and the magnet slots 6 and the positioning holes 3 are arranged in a staggered manner.
[0056] In the above embodiments, taking the positioning holes including three hole positions as an example, the rotor punching sheet of the present application is described by way of example, which is not a limitation to the present application. In other embodiments, the positioning holes can also be provided with 2, 4 or even more hole positions according to needs, and each hole position can cooperate with the positioning tooling in a predetermined posture to make the rotor punching sheet have different predetermined deflection angles.
[0057] Exemplarily, the second hole position of the positioning holes in the above embodiments can be removed, and the remaining two hole positions are reserved as the new first hole position and second hole position. At this time, the corresponding first predetermined deflection angle is 5°.
[0058] Refer to Figure 4, in an optional embodiment, the positioning holes 3 only include a first hole position 31 and a second hole position 32 that can be respectively matched with a positioning tooling. The centers of the first hole position 31 and the second hole position 32 are annularly arrayed on a reference circumference, where the reference circumference is a circumference centered at the center of the annular body 1. The annular body 1 is provided with a limiting structure in the first hole position 31 and the second hole position 32 for cooperating with the positioning tooling. Through the cooperation of the limiting structure, it is possible to effectively cooperate with the positioning tooling in a predetermined posture to limit the annular body 1 in different postures.
[0059] Referring to Figure 2 , an embodiment of the present utility model further provides a motor rotor core, which includes a plurality of the above-mentioned rotor punching sheets and a rotating shaft (not shown in the figure) that is in interference fit with the shaft hole 2 of the annular body 1 of the rotor punching sheet.
[0060] Continuing to refer to Figure 2 , the motor rotor core in this embodiment includes 2X identical rotor core segments to form a V-shaped skewed pole scheme. That is, two groups of X-segment stepped skewed poles, and the skewed pole angle θ = 360° / Y*(X - 1) / X, where Y is the least common multiple of the number of stator slots S of the motor and the number of rotor poles 2P. The deflection angle θ1 between adjacent rotor core segments = θ / (X - 1). This embodiment takes Figure 2 the shown motor as an example, which is a 48-slot 8-pole motor with 6-segment V-shaped skewed poles, that is, this motor is two groups of 3-segment stepped skewed poles. It can be calculated that the skewed pole angle is θ = 360° / 48*(3 - 1) / 3 = 5°. Thus, it can be known that the preset deflection angle between adjacent rotor punching sheets is θ1 = 5 / (3 - 1) = 2.5°. Therefore, during installation, the deflection angle between each group of adjacent rotor punching sheets is set to 2.5°.
[0061] In this embodiment, since there is no need to slot at the shaft hole 2 of the rotor punching sheet, the processing technology is simple and the manufacturing cost is low. And since the inner peripheral wall of the shaft hole 2 of the annular body 1 does not include a limiting structure, the vertical projection of the shaft hole 2 of the annular body 1 in its plane is circular. Therefore, it is convenient to perform an interference fit connection with the rotating shaft through the shaft hole 2. For traditional rotor cores and rotating shafts, they are mostly clearance fits. As the motor speed increases, the deformation amount of the rotor core increases, and the clearance with the rotating shaft also becomes larger, resulting in relatively large vibration and noise of the whole vehicle. The present application can effectively solve the above problems through the interference fit between the shaft hole 2 and the rotating shaft, and reduce the vibration and noise that may occur when the motor is used in an automobile.
[0062] For those skilled in the art, it is obvious that the present utility model is not limited to the details of the above-described exemplary embodiments, and the present utility model can be implemented in other specific forms without departing from the spirit or basic characteristics of the present utility model. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present utility model is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present utility model. Any reference signs in the claims should not be construed as limiting the claimed claim.
[0063] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A rotor punching, characterized in that: It comprises an annular body (1) having an axial hole (2), the annular body (1) being provided with a positioning hole (3), the positioning hole (3) comprising a first hole position (31) and a second hole position (32) which can respectively cooperate with a positioning tool; Wherein, when the annular body (1) is in a first posture, the positioning hole (3) cooperates with a positioning tool of a predetermined posture through the first hole position (31); when the annular body (1) is in a second posture, the positioning hole (3) cooperates with a positioning tool of a predetermined posture through the second hole position (32); a first predetermined deflection angle is set along the annular center axis between the first posture and the second posture of the annular body (1).
2. The rotor punching according to claim 1, characterized in that: The positioning hole (3) further comprises a third hole position (33) cooperating with the positioning tool. When the annular body (1) is in the third posture, the positioning hole (3) cooperates with the positioning tool in the predetermined posture through the third hole position (33); a second predetermined deflection angle is set along the annular axis of the annular body (1) between the second posture and the third posture; Wherein, when the annular body (1) is deflected from the first posture to the third posture, the annular body (1) is deflected along its annular center axis by the sum of the first predetermined deflection angle and the second predetermined deflection angle.
3. The rotor punching according to claim 2, characterized in that: The centers of the first hole positions (31), the second hole positions (32) and the third hole positions (33) are distributed in a circular array on a reference circumference, wherein the reference circumference is a circumference with the center of the annular body (1) as the center; and / or, The first hole position (31), the second hole position (32) and the third hole position (33) are interconnected, and there is an overlapping portion between the first hole position (31) and the second hole position (32), and there is an overlapping portion between the second hole position (32) and the third hole position (33).
4. The rotor punching according to claim 3, characterized in that: The inner circumferential wall of the positioning hole (3) comprises a first inner circumferential wall section defining the first hole position (31), a second inner circumferential wall section defining the second hole position (32), and a third inner circumferential wall section defining the third hole position (33), wherein the vertical projections of the first inner circumferential wall section, the second inner circumferential wall section and the third inner circumferential wall section on the plane where the annular body (1) is located are circular arcs.
5. The rotor punching according to claim 4, characterized in that: The first inner circumferential wall section and the third inner circumferential wall section of the annular body (1) are recessed with positioning key grooves (4) that can cooperate with positioning tooling, and the second inner circumferential wall of the annular body (1) is convexly provided with a positioning key (5) that can cooperate with the positioning tooling.
6. The rotor punching according to claim 1, characterized in that: The centers of the first hole positions (31) and the second hole positions (32) are distributed in a circular array on a reference circumference, wherein the reference circumference is a circumference with the center of the annular body (1) as the center; and / or, The annular body (1) is provided with a limiting structure in the first hole position (31) and the second hole position (32) for cooperating with a positioning tool.
7. The rotor punching according to claim 1, characterized in that: The annular body (1) is provided with a plurality of positioning holes (3), wherein the centers of the first hole positions (31) and the second hole positions (32) of the plurality of positioning holes (3) are distributed in an annular array on a reference circle; and / or The inner peripheral wall of the axial hole (2) of the annular body (1) does not include a limiting structure, and the vertical projection of the axial hole (2) of the annular body (1) on the plane where it is located is circular.
8. A rotor punching, characterized in that: The invention comprises an annular body (1) having an axial hole (2), the annular body (1) being provided with a positioning hole (3), the vertical projection of the positioning hole (3) on the plane where the annular body (1) is located comprising a first circular arc (311), a second circular arc (321) and a third circular arc (331) which are sequentially connected to each other, the first circular arc (311), the second circular arc (321) and the third circular arc (331) having the same radius of curvature, and the centers of the circles where the first circular arc (311), the second circular arc (321) and the third circular arc (331) are located are located on the same circumference with the center of the annular body (1) as the center.
9. The rotor punching according to claim 8, characterized in that: The angle between the center of the circle where the first arc (311) and the second arc (321) are located and the center of the annular body (1) is equal to the angle between the center of the circle where the second arc (321) and the third arc (331) are located and the center of the annular body (1), and the angle is set to achieve a predetermined deflection angle for realizing a motor rotor skew pole mode.
10. A motor rotor core, characterized in that: The invention comprises a plurality of rotor punching sheets as claimed in any one of claims 1 to 9 and a rotating shaft which is interference-fitted with the axial hole (2) of the annular body (1) of the rotor punching sheet.